It's not really a bee in my bonnet, I just believe the Mets decided he wasn't a starter at least in part to that mid-season experiment. By the time Sandy got here I'm not sure taking a random reliever they'd had in that role and converting him to a starter was even ever a consideration. For an organization that was criticized, sometimes unfairly, for rushing guys to the majors, there does seem to be some evidence that they converted Parnell to a reliever in order to help out the 2009 pen. This is a guy who had finished more games in the minors that he started than that as a reliever. (prior to that point) He wasn't particularly successful starting, and he was only a 9th round pick, but as to MFS62's question about making him a starter again now that he's maybe commanded another pitch I think that failed experiment mid-season may have been perceived as the final straw. He wasn't really brought up too fast in order to help the club, he was showing he wasn't a starter and they felt relieving was where his value was.